Prosthetic heart valves are used to replace a patient's own defective or damaged valves. Prosthetic heart valves currently in use are divided into two broad categories:—tissue valves and mechanical valves.
Tissue valves are either naturally-formed valves taken from pig hearts or valves formed from pericardium tissue taken from bovine hearts. In general, tissue valves are well accepted by the patient's body and require only the minimum anticoagulation treatment. However, tissue valves have the drawback that they wear out relatively rapidly, with a life of between 10 and 20 years.
Mechanical valves have excellent durability:—accelerated testing suggests that mechanical valves may have a life of the order of 200 years. However, mechanical valves have the drawback that they are not readily accepted by a patient's body and require long-term anticoagulation treatment to prevent thromboembolic complications. This is undesirable from the point of view of the patient's general health.
It is therefore an object of the present invention to provide a prosthetic valve, more particularly a heart valve, which has the durability of a mechanical valve but which is as compatible with the patient's body as a tissue valve, and thus requires no, or minimal, anticoagulation therapy.